Process for refining alkanesulfonyl chlorides



United ttes I. atnt 3,147,303 PRQCESS FGR REFINING ALKANESULFGNYL QHLOBEDES Hans Stroh, Krefeld, and Harry Welz, Krefeld-Uerdmgen,

Germany, assignors to Farhenfahrikcn Bayer Aktiengesellschaft, Leverkusen, Germany, a corporation of Germany No Drawing. Filed Apr. 13, 1960, Ser. No. 21,863

tllaims priority, application Germany Apr. 25, 1959 7 Claims. (Cl. sea-sis The present invention is concerned with a process for refining alkanesulfonyl chlorides.

It is known to produce alkyl sulphochlorides by the action of chlorine and sulfur dioxide on aliphatic hydrocarbons. These alkanesulfonyl chlorides serve as starting materials for the production of salts and esters of alkanesulfonic acids which are used as detergent raw materials and emulsifiers or plasticizers for synthetic plastic materials. The quality of these alkanesulfonic acid salts and esters with regard to color and thermal stability is dependent, to a large extent, on the degree of purity of the alkanesulfonyl chlorides from which they were prepared. Colorless or very pale and completely stable emulsifiers and plasticizers can only be obtained by saponification r esterification of alkanesulfonyl chlorides produced from pure aliphatic hydrocarbons. Liquid products consisting essentially of a mixture of saturated and unsaturated aliphatic hydrocarbons obtained by catalytic hydrogenation of carbon monoxide in accordance with the Synthol or Fischer-Tropsch processes have been used as starting materials for the production of alkanesulfonyl chlorides. The alkanesulfonyl chlorides produced by treatment of such liquid hydrocarbon mixtures obtained in the Synthol or Fischer-Tropsch process with mixtures of sulfur dioxide and chlorine are suitable starting materials for the production of colorless or pale and stable salts and esters of alkanesulfonic acids only if the liquid hydrocarbon mixtures from which they were prepared had been subjected to hydrogenation to completely saturate the unsaturated hydrocarbons contained therein. The treatment of hydrogenated fractions of such liquid hydrocarbon mixtures with sulfur dioxide and chlorine convert about only 50 percent of the hydrocarbon mixture to alkanesulfonyl chlorides. The unreacted portion of the fraction when treated again with sulfur dioxide and chlorine produces alkanesulfonyl chlorides that yield salts and esters of alkanesulfonic acids that are not colorless.

Alkanesulfonyl chlorides produced from selected fractions of petroleum or mineral oils by treatment with sulfur dioxide and chlorine also formed sulfonic acid salts and esters that were dark brown or black in color. The unsatisfactory quality of such alkanesulfonyl chlorides is due to the high content in the mineral oil of aromatic and cycloaliphatic (naphthene), as well as branched-chain aliphatic hydrocarbons. It has, therefore, been proposed to remove the undesired compounds by different types of refining processes. Such refining processes are, for example, treatments with concentrated sulfuric acid, phosphosulfuric acid or selective solvents. Nevertheless, such refining methods only lead to a complete removal of the aromatic hydrocarbons whereas the cycloaliphatic hydrocarbons remain, to a large extent, in the mineral oil fractions. The mineral oil fractions refined in this manner are, therefore, even after complete hydrogenation, not suitable for the production of colorless sulfonic acid salts and esters with adequate stability characteristics.

It is also known to use as raw materials for the production of alkanesulfonates, oils produced by the cracking or hydrogenation cracking of high-boiling aliphatic hydrocarbons, such as crude parafiin, soft or hard parafiins from mineral oil or tar from low-temperature carbonization.

Patented Sept. 1, 1964 7 ice However, since the starting materials for the cracking usually contain not only pure aliphatic hydrocarbons but are also contaminated with crude mineral oil or tar, such substances are likewise not suitable starting hydrocarbon materials for the production of alkanesulfonyl chlorides which yield salts and esters of sulfonic acids that have a sufficiently bright color and sufficient stability.

We have now found that colorless or very pale and stable salts and esters of sulfonic acids can be obtained from substantially saturated aliphatic hydrocarbons with about 10 to about 20 carbon atoms, even from those raw materials which were hitherto unsuitable for the produc tion of such products, such as refined mineral oil products, cracked products from high-boiling paraflinic fractions of mineral oils or low-temperature carbonization tars, polymerization products from unsaturated aliphatic hydrocarbons and residual oils which remain after the treatment of aliphatic hydrocarbons with sulfur dioxide and chlorine, if the alkanesulfonyl chlorides produced therefrom by treatment with sulfur dioxide and chlorine or mixtures of the starting hydrocarbon material and such alkanesulfonyl chlorides are treated or subjected to refining with oxygen-containing acids of hexavalent sulfur or anhydrides of such acids.

Sulfuric acids having with a concentration of at least percent, of H 80 by weight especially those containing more than percent, fuming sulfuric acid, chlorosulfonic acid or sulfuric trioxide (sulfuric acid anhydride) have proved to be particularly suitable refining agents.

The refining treatment of the present invention can be effected simply by mixing the acid with the alkanesulfonyl chloride or with the mixture of the starting oil and alkanesulfonyl chloride or, in the case of gaseous refining agents, such as sulfur trioxide, by passing the gas through the alkanesulfonyl chloride in an undiluted condition or admixed with an inert gas.

By such a treatment with the refining agents in accordance with the process of the present invention, labile alkanesulfonyl chlorides are removed which cause the formation of colored compounds in the subsequent saponification or esterification. The greater part of the refining agent separates out, after the refining, as a heavy layer on the bottom of the refining vessel and can, there fore, be easily separated. Resinous products that are formed during the refining are dissolved in the refining agent. Complete removal of the refining agent can be effected either by centrifuging or by treatment with adsorbents, such as fullers earth, and subsequent filtration. Removal of the refining agent is also possible by washing with water with which can be admixed small amounts of alkalis or salts. The treatment with fullers earth has proved to be the best method.

The refining of the alkanesulfonyl chlorides can be effected in either batchwise or continuous operations in one or more stages. The multistage continuous process can be carried out concurrently or countercurrently. In the countercurrent operation, only a very small amount of refining agent is used.

The temperature necessary for the refining process of the present invention depends on the quality of the starting alkanesulfonyl chloride and on the desired degree of refining. The refining can, in most cases, be carried out at room temperature. The temperature is limited at the lower level by the solidification point of the alkanesulfonyl chloride or of the refining agent used and is upwardly limited by the thermal decomposition of the alkanesulfonyl chloride which commences at elevated temperatures.

The amount of refining agent necessary for the refining depends upon the acid concentration, the quality of the starting alkanesulfonyl chloride and the desired degree of refining. In most cases 5-30 percent suffices.

The following examples are given for the purpose of illustrating the present invention:

Example 1 An oil obtained by refining a mineral oil-diesel oil fraction with liquid sulfur dioxide and subsequent hydrogenation (analytical data: (1 0.7952, index of refraction (11 1.4430, boiling range 220-305 C.) is treated at 30 C. with a mixture of sulfur dioxide and chlorine while the reaction mixture is irradiated with a tungsten filament lamp for two hours. After the reaction, the reaction mixture consists of 25 percent organic sulfonyl chlorides and 75 percent unreacted oil.

The reaction mixture is treated three times at 25 C. with a volume of 98-percent sulfuric acid equivalent to percent of the volume of the reaction mixture. The refining is carried out in a glass vessel with intensive stirring. After the refining, the sulfuric acid has become dark brown in color. It settles to the bottom of the vessel and can easily be separated by decantation. After the refining, the oil layer is treated with 4 percent of fullers earth and filtered. The refining loss amounts to 6 percent.

The mixture of alkanesulfonyl chlorides and unreacted starting oil is reacted with a 10 percent sodium hydroxide solution at 100 C. and the alkanesulfonyl chlorides contained therein are thereby converted into sodium salts of the corresponding alkanesulfonic acids. After this reaction, the reaction mixture separates into two layers, an oil layer and an aqueous layer in which all of the sulfonates are dissolved. The further working up of the sulfonates solution takes place by cooling to +6 C. whereby two layers are formed. The upper layer contains the greater part of the sulfonates and a part of the unreacted oil, while the lower layer consists essentially of a solution of sodium chloride. The upper layer is evaporated and the oil separated from the sulfonates by a vacuum steam distillation at 180 C. The remaining sulfonates melt consists of 9596 percent sulfonates. Two samples were subjected to this treatment, one being a mixture of alkanesulfonyl chlorides and unreacted oil that had not been refined in accordance with the process of this invention while the other was refined with sulfuric acid as described hereinbefore.

The mixture of sodium alkanesulfonates obtained from the refined mixture of alkanesulfonyl chlorides had a pure white color. A 30 percent aqueous solution of this mixture of sodium alkanesulfonates had a color number of 2 in a 4 cm. tube (Gardner scale, see Paint Testing Manual by Henry Alford Gardner, published Bethesda, Maryland). The mixture of sodium alkanesulfonates obtained from the unrefined mixture of alkanesulfonyl chlorides had a brown color. A 30 percent aqueous solution had a color number of 12 on the same scale.

Example 2 A middle oil obtained by the hydrogenation cracking of a mineral oil-crude parafiin (analytical data: d 0.771, index of refraction (21 1.4332, boiling range 218- 314 C.), is treated with a mixture of sulfur dioxide and chlorine at 30 C. while it was irradiated with a tungsten filament lamp. The degree of reaction amounts to 26 percent. The reaction mixture is refined at 30 C. in a continuous countercurrent manner in two stages with 10 percent of 98 percent by volume sulfuric acid. Separation of the sulfuric acid also was conducted continuously in a subsequent separator. The oil layer is subsequently treated with 3 percent of fullers earth and filtered. The refining loss amounts to 4.5 percent.

The saponification of the refined and unrefined mixtures of oil and alkanesulfonyl chlorides and the recovery of the alkanesulfonates is conducted under the same conditions as specified in Example 1. In the case of the refined mixture of alkanesulfonyl chlorides, a white sulfonate is obtained which, in a 30 percent solution,

Example 3 An unreacted residual oil recovered after the treatment with a mixture of sulfur dioxide and chlorine of a hydrogenated diesel oil that produced a yield of 50 percent of alkanesulfonyl chlorides having the following analytical data: (1 0.771, boiling range 2303l8 C. is again treated with a mixture of sulfur dioxide and chlorine at 30 C. while it was irradiated with a tungsten filament lamp. The reaction amounts to 50 percent. The reaction mixture is treated at 30 C. with a mixture of percent air and 10 percent sulfur trioxide. At the end of this refining treatment, a dark brown acid layer which can be easily separated settles to the bottom of the refining vessel. The oil layer is subsequently treated with 3 percent of fullers earth and filtered. The refining loss amounts to 4 percent.

The saponification of the refined and unrefined mixtures of oil and alkanesulfonyl chlorides and the recovery of the alkanesulfonates is conducted under the same con ditions as specified in Example 1. A White sulfonate is obtained from the refined mixture of alkanesulfonyl chlorides which shows a color number of 1 in a 30 percent solution. A yellow sulfonate is obtained from the unrefined mixture of alkanesulfonyl chlorides. The color number of the 30 percent solution is 5.

Example 4 Another portion of the hydrogenated mineral oil fraction described in Example 1 is treated with a mixture of sulfur dioxide and chlorine until the content of saponifiable chlorine amounts to 5.6 percent. The resulting mixture of alkanesulfonyl chlorides is treated three times at 25 C. with 5 percent by weight of 98-peroent sulfuric acid and then with 3 percent of fullers earth. The re fined product thus obtained is esterified in conventional manner with a mixture of equal parts of phenol and cresol in the presence of sodium hydroxide solution and freed from neutral oil by a vacuum steam distillation. The ester obtained has an iodine color number of 6 (milligrams of iodine in 100 milliliters of solution) while the ester obtained in the same manner from the corresponding unrefined product has an iodine color number of 70. The iodine color number is the number of milligrams of free iodine that are present in an aqueous solution of iodine containing potassium iodide which equals the color intensity of the sample in strata having a thickness of 10 millimeters (see C. F. Spiess and Werner Eissner, Farbe u. Lack, vol. 59, pages 229-231 (1953); Chemical Abstracts, vol 47, column 9630a; see also Deutsche Normenblatt DIN 6162 of the Deutsches Normenausschusses, published February 1956 by the Beuth-Vertrieb GmbH, Berlin W15, Germany).

Example 5 An oil obtained by the polymerization of propylene and having a boiling range of 197 C. is treated with a mixture of sulfur dioxide and chlorine until the resulting product has a content of 5.88 percent saponifiable chlorine. The resulting alkanesulfonyl chloride is refined by washing three times with 5 percent by weight of 98-percent sulfuric acid whereby a loss of 9 percent of alkanesulfonyl chloride takes place. The reaction of this refined alkanesulfonyl chloride with a phenol-cresol mixture in known manner gives an ester with an iodine color number of 6, where as an ester of the unrefined alkanesulfonyl chloride has an iodine color number of about 215.

Example 6 A fraction obtained by hydrogenation cracking of a mineral oil having a boiling range of 2183l1 C. is treated with a mixture of sulfur dioxide and chlorine to a content of 6.34 percent saponifiable chlorine and subsequently treated at 25 C. with a mixture of 90 percent air and percent sulfur trioxide from a contact sulfuric acid plant, with slow stirring, whereby about 6 percent of sulfur trioxide, based on the alkanesulfonyl chloride, is used. After pouring the dark alkanesulfonyl chloride from the resinous residue that was formed and treatment with 1.5 percent of fullers earth, a 3.5 percent of the product was lost. The phenyl-cresyl ester produced from the refined product has an iodine color number of 1, whereas an ester produced in the same manner from the unrefined alkanesulfonyl chloride has a color number of 3.

What we claim is:

1. In a process for the production of a mixture containing alkanesulfonyl chlorides by the reaction of a mixture of saturated aliphatic hydrocarbons the molecules of which contain between 10 and 20 carbon atoms with a mixture of sulfur dioxide and chlorine, the improvement which consists in refining the reaction mixture by contacting it with a substance of the group consisting of sulfuric acid having a concentration of at least 80% of H SO by weight, fuming sulfuric acid, chlorosulfonic acid, and sulfur trioxide, in an amount between about 5 and 30% by weight of the reaction mixture, at a temperature between the solidification and the decomposition points of the mixture, and subsequently separating the resulting refined mixture of alkanesulfonyl chlorides from the refining agent.

2. A process as defined in claim 1 in which the refined mixture of alkanesulfonyl chlorides is subsequently subjected to refining treatment with fullers earth.

3. A process as defined in claim 1 in which the mixture of alkanesulfonyl chlorides is refined by contacting it with sulfuric acid having a concentration of at least of H SO by weight.

4. A process as defined in claim 1 in which the mixture of alkanesulfonyl chlorides is refined by contacting it with fuming sulfuric acid.

5. A process as defined in claim 1 in which the mixture of alkanesulfonyl chlorides is refined by contacting it with chlorosulfonic acid.

6. A process as defined in claim 1 in which the mixture of alkanesulfonyl chlorides is refined by contacting it with sulfur trioxide.

7. A process as defined in claim 1 in which the refining treatment is performed at room temperature.

References Cited in the file of this patent UNITED STATES PATENTS 2,197,800 Henke et al Apr. 20, 1940 2,263,312 Reed Nov. 18, 1941 2,412,679 Grubb et al. Dec. 17, 1946 2,581,064 Archibald Jan. 1, 1952 

1. IN A PROCESS FOR THE PRODUCTION OF A MIXTURE CONTAINING ALKANESULFONYL CHLORIDES BY THE REACTION OF A MIXTURE OF SATURATED ALIPHATIC HYDROCARBONS THE MOLECULES OF WHICH CONTAIN BETWEEN 10 AND 20 CARBON ATOMS WITH A MIXTURE OF SULFUR DIOXIDE AND CHLORINE, THE IMPROVEMENT WHICH CONSISTS IN REFINING THE REACTION MIXTURE BY CONTACTING IT WITH A SUBSTANCE OF THE GROUP CONSISTING OF SULFURIC ACID HAVING A CONCENTRATION OF AT LEAST 80% OF H2SO4 BY WEIGHT, FUMING AULFURIC ACID, CHLOROSULFONIC ACID, AND SULFUR TRIOXIDE, IN AN AMOUNT BETWEEN ABOUT 5 AND 30% BY WEIGHT OF THE REACTION MIXTURE, AT A TEMPERATURE BETWEEN THE SOLIDIFICATION AND THE DECOMPOSITION POINTS OF THE MIXTURE, AND SUBSEQUENTLY SEPARATING THE RESULTING REFINED OF ALKANESULFONYL CHLORIDES FROM THE REFINING AGENT. 